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Commitments and Contingencies - Commitments (Details) $ in Millions, $ in Millions | Dec. 31, 2020 CAD ($) | Jul. 30, 2015 USD ($)
--- | --- | ---
Disclosure of Commitments [Line Items] |  |
Coal supply and mining agreements | $ 410 |
Long-term service agreements | 173 |
Operating leases | 36 |
Growth | 1,013 |
TransAlta Energy Transition Bill | 18 | $ 55
Total | 3,733 |
Natural gas, transportation and other contracts |  |
Disclosure of Commitments [Line Items] |  |
Purchase obligations | 2,048 |
Transmission |  |
Disclosure of Commitments [Line Items] |  |
Purchase obligations | 35 |
2021 |  |
Disclosure of Commitments [Line Items] |  |
Coal supply and mining agreements | 81 |
Long-term service agreements | 31 |
Operating leases | 4 |
Growth | 509 |
TransAlta Energy Transition Bill | 6 |
Total | 780 |
2021 | Natural gas, transportation and other contracts |  |
Disclosure of Commitments [Line Items] |  |
Purchase obligations | 141 |
2021 | Transmission |  |
Disclosure of Commitments [Line Items] |  |
Purchase obligations | 8 |
2022 |  |
Disclosure of Commitments [Line Items] |  |
Coal supply and mining agreements | 105 |
Long-term service agreements | 37 |
Operating leases | 2 |
Growth | 411 |
TransAlta Energy Transition Bill | 6 |
Total | 718 |
2022 | Natural gas, transportation and other contracts |  |
Disclosure of Commitments [Line Items] |  |
Purchase obligations | 149 |
2022 | Transmission |  |
Disclosure of Commitments [Line Items] |  |
Purchase obligations | 8 |
2023 |  |
Disclosure of Commitments [Line Items] |  |
Coal supply and mining agreements | 101 |
Long-term service agreements | 22 |
Operating leases | 2 |
Growth | 93 |
TransAlta Energy Transition Bill | 6 |
Total | 369 |
2023 | Natural gas, transportation and other contracts |  |
Disclosure of Commitments [Line Items] |  |
Purchase obligations | 137 |
2023 | Transmission |  |
Disclosure of Commitments [Line Items] |  |
Purchase obligations | 8 |
2024 |  |
Disclosure of Commitments [Line Items] |  |
Coal supply and mining agreements | 67 |
Long-term service agreements | 18 |
Operating leases | 1 |
Growth | 0 |
TransAlta Energy Transition Bill | 0 |
Total | 225 |
2024 | Natural gas, transportation and other contracts |  |
Disclosure of Commitments [Line Items] |  |
Purchase obligations | 134 |
2024 | Transmission |  |
Disclosure of Commitments [Line Items] |  |
Purchase obligations | 5 |
2025 |  |
Disclosure of Commitments [Line Items] |  |
Coal supply and mining agreements | 56 |
Long-term service agreements | 10 |
Operating leases | 1 |
Growth | 0 |
TransAlta Energy Transition Bill | 0 |
Total | 206 |
2025 | Natural gas, transportation and other contracts |  |
Disclosure of Commitments [Line Items] |  |
Purchase obligations | 134 |
2025 | Transmission |  |
Disclosure of Commitments [Line Items] |  |
Purchase obligations | 5 |
2026 |  |
Disclosure of Commitments [Line Items] |  |
Coal supply and mining agreements | 0 |
Long-term service agreements | 55 |
Operating leases | 26 |
Growth | 0 |
TransAlta Energy Transition Bill | 0 |
Total | 1,435 |
2026 | Natural gas, transportation and other contracts |  |
Disclosure of Commitments [Line Items] |  |
Purchase obligations | 1,353 |
2026 | Transmission |  |
Disclosure of Commitments [Line Items] |  |
Purchase obligations | $ 1 |

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- Definition The amount of capital commitments for which the entity has entered into a contract. [Refer: Capital commitments] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_112_c&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The amount of contractual undiscounted cash flows in relation to lease liabilities before deducting finance charges. [Refer: Lease liabilities] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 16 -IssueDate 2019-01-01 -Paragraph 58 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2019-en-r&anchor=para_58&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 7 -IssueDate 2019-01-01 -Paragraph B11D -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_B11D_a&doctype=Appendix&subtype=B -URIDate 2019-03-27 + Details
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